The biochemistry of build-up and breakdown of cuticle in the molt will be studied. A survey of enzymes involved in breakdown of chitin in cuticle will be made. Chitinases will be compared to citnases from other organisms, isolated by affinity chromatography on agarose, and characterized. Chitins and chitodextrius will also be isolated and characterized, the former by High Performance Liquid Chromatography. Insect chitin synthesis will be further elucidated, and the chitin-protein link will be studied. This investigation is aimed at delineating the biochemistry of arthropod molting in order to permit the rational design of insecticides and antimycotics. One of the chief features that distinguish arthropods from vertebrates is the possession of a chitinous exoskeleton which must periodically be molted, i.e., replaced; fungi, too, are protected by a tough chitinous covering. Arthropods and fungi interact with man in a myriad of ways: as pollinators of foot crops; as vectors or causative organisms of serious diseases such as malaria, typhus, plague, and mycoses; as parasites; as decomposers; as predators on harmful organisms (beneficials); as essential links in food chains. Man in his efforts to control the harmful effects of these organisms, adversely affects his own health and well-being and that of other animals by use of broad-spectrum, highly poisonous chemicals, such as organochlorines and alkymercurials. The studies in this laboratory are aimed at better understanding of a little known but vitally important facet of biochemistry so that quicker, surer, and more specific means may be found that will permit interference with harmful but not beneficial organisms. The very alienness of the biochemistry of chitin should thus be seen as an asset; its basic understanding will permit a rational instead of a sledgehammer approach to areas vitally affecting human health.